HVAC Efficiency

What It Is

HVAC (heating, ventilating, and air conditioning) efficiency reduces the amount of energy you need to control temperature and air flow in a space. Methods for improving HVAC efficiency include using or reducing natural light, repairing air leaks, installing a programmable thermostat, and replacing old HVAC equipment.

Why It Matters

According to the US Small Business Administration, “mechanical air conditioning accounts for the largest percentage of energy use in both residential and commercial buildings. Not only that, building codes are becoming more stringent, and there is a greater need to improve the indoor air quality for better worker performance.”[1]

HVAC efficiency helps you use less energy to control temperature in a space, which cuts down on your utility bill. HVAC efficiency also controls humidity levels, which helps reduce bacteria and mold growth and improve air quality.[2]

Check your filter once a month to make sure it’s clean, since a dirty filter will slow airflow, making the system work harder. Furthermore, the dust and debris from a dirty filter can build up in the system, causing it to break down. The ENERGY STAR Program recommends changing your filter at least every three months.[4]

Step Two

“Just as a tune-up for your car can improve your gas mileage, a yearly tune-up of your heating and cooling system can improve efficiency and comfort.”[5] For more information, check out these links from ENERGY STAR:

For controlling temperature in a space, south- and north-facing windows are best. They let in natural light while “producing little glare and almost no unwanted summer heat.” South-facing windows are also particularly good for natural lighting and heating in the wintertime.[6]

Make sure to shade east- and west-facing windows because they often cause glare, admit a lot of heat during the summer, and contribute little to solar heating during the winter.[7]

Check out the How To Guide Article, Energy Efficient Lighting, for more information on natural lighting and other energy-efficient light sources.

Step Four

Cracks around doors and windows let cool air escape in the summer and warm air escape in the winter, raising your utility bill.

You can easily detect some air leaks because you will feel a draft coming from the window or door. However, smaller leaks are harder to find. Energy Savers suggests using the following steps to detect smaller leaks:

Shut all windows and doors

Turn on all exhaust fans to depressurize the space

Light an incense stick and pass it around the edges of common leak sites. If the smoke is sucked out or blown into the room, there’s a draft.[8]

An energy audit (i.e., assessment) can also help you identify air leaks, as well as other energy inefficiencies. For example, a professional energy auditor can conduct a blower door test, using a powerful fan to depressurize your space so that he/she can better detect leaks. In many cases, federal and local governments will help fund energy audits, making the process more affordable. So be sure to check Grants.gov and your local government website.

Going Further

Step One: Install a programmable thermostat

Step Two: Install motion or occupancy sensors

Step Three: Double-pane windows

Step Four: ENERGY STAR equipment

Step One

A programmable thermostat turns the HVAC system on or off at scheduled times. This ensures that the system is on when needed and off when not. “Through proper use of pre-programmed settings, a programmable thermostat can save you about $180 every year in energy costs.”[9]

Step Two

Motion and occupancy sensors heat or cool the office only when people are using the space. The sensors switch the HVAC system off when the space is empty, reducing the electricity bill.

Step Three

Installing double-pane windows can reduce air leaks because they better prevent air from escaping or entering the space. Check out GreenYour.com to learn how to buy and install double-pane windows.

Step Four

If you need to update or replace your HVAC system, shop for new, energy-efficient equipment from ENERGY STAR. “Replacing your old heating and cooling equipment with ENERGY STAR qualified equipment can cut” $200 from your energy bill. This list of indicators can help you figure out if you need to replace your system. However, when in doubt, have a professional HVAC contractor evaluate your system.

Also, make sure that your new equipment is installed correctly, as improper installation wastes energy and money.

Case Study

The “stale smell” and “lack of fresh air” inside the Kings Pharmacy in Brooklyn, New York annoyed both its owners and customers. To improve comfort and indoor air quality, as well as lower the utility bills, the owners installed two new economizers on the existing units, cleaned the evaporator coils, replaced the system’s filters and belts, and installed two programmable thermostats.[10]

These changes save them over $2,000 a year. For more information on this case, click here.

Green Plus teamed up with the Center for Sustainable Tourism at Eastern Carolina University on this podcast on HVAC Systems

Conclusion

Improving the efficiency of your HVAC system saves energy and money while making the workplace more comfortable for employees and customers. Simple steps, such as changing your air filter, can increase HVAC efficiency. More advanced steps, such as installing occupancy sensors and ENERGY STAR equipment, can result in even bigger savings.

[1] “Tips for Energy Efficiency,” US Small Business Administration, http://www.sba.gov/content/tips-energy-efficiency, accessed 23 July 2013.

[2] “Tips for Energy Efficiency,” US Small Business Administration, http://www.sba.gov/content/tips-energy-efficiency, accessed 23 July 2013.

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